In a writing instrument that includes a capillary reservoir, a capillary connector transfers ink from the capillary reservoir to the writing head, which may be either an independent part or the front end portion of the connector. The capillary reservoir usually consists of an array of fibers. The fibers may be acetate or polyester fibers, for example.
As the instrument is used, the ink that is consumed from the writing head is replaced with ink from the capillary reservoir. A major drawback of that type of instrument is that not all of the ink that is injected into the capillary reservoir during fabrication of the instrument is delivered for writing. It is found that a certain proportion of the ink contained in the capillary array of the reservoir remains there at the end of the life of the instrument. The proportion of the ink that is not delivered is generally estimated at around 20%.
This is a drawback in more ways than one. Firstly, the unconsumed ink increases the cost of the instrument. Secondly, the residual ink pollutes the environment. Finally, the residual ink causes problems with recycling spent instruments.